title: Femtosecond laser nanomachining initiated by ultraviolet multiphoton ionization.
abstract: We report on the experimental results of 300 nm features generated on fused silica using a near-infrared (IR) femtosecond laser pulse initiated by an ultraviolet (UV) pulse. With both pulses at a short (~60 fs) delay, the damage threshold of the UV pulse is only 10% of its normal value. Considerable reduction of UV damage threshold is observed when two pulses are at ± 1.3 ps delay. The damage feature size of the combined pulses is similar to that of a single UV pulse. A modified rate equation model with the consideration of defect states is used to help explain these results. This concept can be applied to shorter wavelengths, e.g. XUV and X-ray, with the required fluence below their normal threshold.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yu
authors.forename: Qiumei
authors.initials: Q
authors.lastname: Bian
authors.forename: Zenghu
authors.initials: Z
authors.lastname: Chang
authors.forename: P B
authors.initials: PB
authors.lastname: Corkum
authors.forename: Shuting
authors.initials: S
authors.lastname: Lei